What if the World Population Reaches UN Estimates?

May 13, 2011

The United Nations, according to the media, predicts that the world's population will be 10.1 billion by the end of the century, says Richard Posner, a senior lecturer at the University of Chicago Law School.

The United Nations report offers three predictions -- a high, medium and low -- depending on different assumptions.

The high is almost 16 billion and the low 6.2 billion (which is actually lower than the current world population).

Of course much could happen between now and then to push the world population far outside the range. So how realistic is such an expectation?

Much depends on changes in the status of women.

If employment and wage rates of women rise, thus increasing the opportunity costs of children, birth rates will decline.

These changes are likely to be correlated with increased wealth, which in turn will accelerate the fall of death rates in these countries.

But the decline in death rates is likely to be less than the decline in birth rates, and if so the rate of population increase will slow in the high-fertility countries.

Would a world population of 10.1 billion be a good or a bad thing? Arguably a good thing, on several grounds.

One is that it would enable greater specialization, which reduces costs.

Second is that it would increase the returns to innovation by increasing the size of markets, though an offset is that innovation can produce immensely destructive as well as constructive technology.

Third, the more people there will be, the more high-IQ people there will be, and hence the faster the growth of knowledge will be.

Fourth, if the total subjective welfare of the 10.1 billion exceeds that of a smaller population, or the average welfare of the greater population is greater than that of the smaller one, the world will be a happier place in a utilitarian sense (the excess of pleasure over pain will be greater).

The downside of population growth is the pressure it places on the environment and natural resources, especially the former, since the price system provides efficient rationing of resource use, says Posner.